1. Field of the Invention
The present invention relates to a semiconductor device and method of fabricating the same. More particularly, the present invention relates to a bipolar junction transistor structure and method of fabricating the same.
2. Description of the Related Art
In the modem integrated circuit design, bipolar junction transistors are often used in high voltage, high power or high frequency sections as well as places requiring quick switching. Bipolar junction transistors includes p-n-p junction type and n-p-n junction type. The n-type collector of a typical n-p-n bipolar junction transistor is an n-type well formed in a p-type substrate. The p-type base is a p-type well formed within the n-type well. The n-type emitter is an n-doped region within the p-type well. Since the p-type base contacts with the n-type collector directly, reverse junction leakage is a serious problem. Moreover the current gain of the bipolar junction transistor is low.